Adam Winstock, the consultant psychiatrist and addiction medicine specialist who founded the survey, said: “Four percent of people were reporting persistent numbness and tingling in their fingers and toes.”
Regular, frequent users, are at risk of peripheral neuropathy, although it is reversible.
He added: “It’s not that this drug is dangerous but if you are taking it at that sort of level, it will deplete your levels of vitamin B12.”
survey of people who self inject for B12 deficiency. 
How are my b12 levels
Blood test results show my vitamin B12 level is 2000
